Power usage monitoring of power feed circuits using power distribution units

ABSTRACT

A method of monitoring power usage includes 1) accessing power usage data for power distribution unit infeeds of a plurality of power distribution units; 2) accessing stored circuit descriptions describing interconnections of the power distribution unit infeeds to a number of power feed circuits; 3) transforming the plurality of power distribution units into a power usage monitor for monitoring power usage of the power feed circuits by aggregating at least some of the power usage data based on the interconnections of the power distribution unit infeeds to the number of power feed circuits; and 4) outputting representations of the aggregated power usage data.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of U.S. patent application Ser. No.13/429,004, filed Mar. 23, 2012, titled POWER USAGE MONITORING OF POWERFEED CIRCUITS USING POWER DISTRIBUTION UNITS and is hereby incorporatedby reference in its entirety.

BACKGROUND

Computing facilities such as data centers generally include electronicequipment racks, such as standard RETMA racks, that commonly compriserectangular or box-shaped housings sometimes referred to as cabinets orracks and associated components for mounting equipment, associatedcommunications cables, and associated power distribution cables.Electronic equipment is commonly mounted in such racks so that thevarious electronic devices are aligned vertically one on top of theother in the rack. Often, multiple such racks are oriented side-by-side,with each containing numerous electronic components and havingsubstantial quantities of associated component wiring located bothwithin and outside the area occupied by the racks. Such racks commonlysupport equipment that is used in a computing network.

In many cases, computing facilities such as server farms or data centerssupport large networks, referred to as enterprise networks. Enterprisenetworks exist to support large world-wide organizations and depend on acombination of technologies, e.g., data communications, inter-networkingequipment such as frame relay controllers, asynchronous transfer mode(ATM) switches, routers, integrated services digital network (ISDN)controllers, application servers, and network management applicationsoftware. Such enterprise networks can be used to support a largecompany's branch offices or campuses throughout the world and, as such,these networks have become mission critical to the functioning of suchorganizations. Masses of information are routinely expected to beexchanged, and such information exchanges are necessary to carry on thedaily business of modern organizations. For example, some internationalbanks have thousands of branch offices placed throughout Europe, Asiaand North America that each critically depend on their ability tocommunicate banking transactions quickly and efficiently with oneanother and with their respective headquarters. A typical enterprisenetwork uses building blocks of router and frame relay networkappliances mounted in equipment racks. Such equipment racks aredistributed to remote point of presence (POP) locations in theparticular network. Each equipment rack can include, for example, framerelay controllers, routers, ISDN controllers, servers, network attachedstorage devices, modems, etc., each of which is connected to one or morepower sources.

Many equipment racks may be located in a data center, with each rackhaving one or more associated power distribution units (PDUs). One ormore such data centers may serve as data communication hubs for anenterprise. On the other hand, more than one enterprise may usecomputing facilities in a single data center. In any event, a particularenterprise and/or a particular data center may have a large number ofequipment racks and associated PDUs.

A conventional PDU is an assembly of electrical outlets (also calledreceptacles) that receive electrical power from a source and distributethe electrical power to one or more separate electrical appliances. Eachelectrical appliance has one or more power cords plugged into one ormore of the outlets. A PDU also typically has a power cord, which can bedirectly hard wired to a power source or plugged into a power sourceusing a traditional plug and receptacle connection. PDUs are used inmany applications and settings such as, for example, in or on electronicequipment racks. One or more PDUs are commonly located in an equipmentrack or other cabinet, and may be installed together with other devicesconnected to the PDU, such as environmental monitors, temperature andhumidity sensors, fuse modules or communications modules that may beexternal to or contained within the PDU housing. A PDU that is mountablein an equipment rack or cabinet may sometimes be referred to as acabinet PDU, or “CDU” for short.

PDUs have been provided with sensors that enable them to sense powerusage at their input or outputs, or environmental conditions liketemperature and humidity. PDUs have also been provided with variousdisplays, indicators and alarm mechanisms that enable the PDUs to reportor indicate the status of power usage and environmental conditionslocally, and with communication interfaces that enable the PDUs toreport or indicate the status of power usage and environmentalconditions to a network power manager (i.e., a power manager connectedto a PDU across a network). In this manner, the power usage andenvironmental information may be used to monitor power usage andenvironmental conditions of both the PDU and the equipment it powers. Insome cases, the power distributed by a PDU may also be controlled (e.g.,power to its outlets may be turned off or on).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 provides an example of how power may be distributed to a server,electrical appliance or device housed in a data center.

FIG. 2 provides an example of a layout for a data center housing severalelectrical equipment racks.

FIG. 3 shows how the infeeds of PDUs mounted in the racks shown in FIG.2 might be connected to a number of power feed circuits.

FIG. 4 provides an example of a rack-mounted PDU.

FIG. 5 shows how a plurality of rack-mounted PDUs might be coupled to anetwork power manager over a network.

FIG. 6 provides an example of a method for monitoring power usage.

FIG. 7 provides an example of a power usage monitoring system.

FIGS. 8-15 illustrate various screen images of a graphical userinterface used by a power usage monitoring system.

FIG. 16 illustrates a computer readable medium storing instructionsthat, when executed by a computer, cause the computer to instantiate apower usage monitor.

FIG. 17 illustrates a method of facilitating power usage monitoring.

DETAILED DESCRIPTION

Disclosed herein are systems, devices, methods, and software formonitoring the power usage of power feed circuits that supply power topower distribution units. In some cases, the power distribution unitsmay be mounted in or on the equipment racks of a data center and may bereferred to as “rack-mounted power distribution units” or “rack-mountedPDUs.”

This description provides examples, and is not intended to limit thescope, applicability or configuration of the invention. Rather, theensuing description will provide those skilled in the art with anenabling description for implementing embodiments of the invention.

Various changes may be made in the functions and arrangements of theprocedures and elements disclosed herein. Thus, various embodiments mayomit, substitute, or add various procedures or elements as appropriate.For instance, it should be appreciated that the disclosed methods may beperformed in orders different than those described, and various stepsmay be added, omitted or combined. Also, aspects and elements describedwith respect to certain embodiments may be combined in various otherembodiments. It should also be appreciated that the following systems,methods, devices, and software may individually or collectively becomponents of a larger system, wherein other procedures or elements maytake precedence over or otherwise modify their application.

The following patents and patent applications are incorporated herein byreference in their entirety: U.S. patent application Ser. No.12/344,419, now U.S. Pat. No. 8,494,661, filed Dec. 26, 2008, titledPOWER DISTRIBUTION, MANAGEMENT, AND MONITORING SYSTEMS AND METHODS; andU.S. patent application Ser. No. 12/717,879, now U.S. Pat. No.8,321,163, filed Mar. 4, 2010, titled MONITORING POWER-RELATEDPARAMETERS IN A POWER DISTRIBUTION UNIT.

FIG. 1 provides an example of how power may be distributed to a server108, electrical appliance or device housed in a data center. In thisexample, power is received into the data center from a power utility andprovided via input switch gear and distribution components (e.g.,voltage switches, regulators and distribution panels) to anuninterruptible power supply (UPS) 100. Alternately, power is providedto the UPS 100 via a battery backup source.

Power received by the UPS 100 is routed to a PDU 102, typicallyfloor-mounted, that is capable of supplying power to the servers 108 andother electrical components mounted in several electrical equipmentracks 106. The form and purpose of the PDU 102 differs from the form andpurpose of the rack-mounted PDUs 110, 112.

The power provided by the floor-mounted PDU 102 is received anddistributed at a structure such as a Remote Power Panel (RPP) 104 orCritical Power Panel (CPP). The RPP 104 receives power at an infeed anddistributes the power to a plurality of power feed circuits (also knownas branch circuits). Each of the power feed circuits is connected to theinfeed of the RPP 104 via one or more circuit breakers of the RPP 104.The power feed circuits may take single-phase or polyphase (e.g.,two-phase or three-phase) forms, and a single RPP 104 may divide itsreceived power (typically three-phase power) amongst variouscombinations of single-phase and polyphase power feed circuits. Asingle-phase power feed circuit (or single phase of power in a polyphasepower feed circuit) is typically referred to as a line of power. Asingle-phase power feed circuit therefore provides one line of power; atwo-phase power feed circuit provides two lines of power; and athree-phase power feed circuit provides three lines of power.

Power is provided from the RPP 104 to a plurality of rack-mounted PDUs110, 112 and/or other electrical components. The rack-mounted PDUs 110,112 may take single-phase or polyphase forms, and may therefore beconnected to different types of power feed circuits. Although FIG. 1shows only a single electrical equipment rack 106 having two PDUs 110,112 mounted therein, a power feed circuit would typically provide powerto several PDUs mounted in several electrical equipment racks. The powerreceived at an infeed of a PDU 110 or 112 (sometimes referred to hereinas a “rack-mounted power distribution unit infeed”) is then distributedto one or more servers 108, electrical appliances or devices.

FIG. 2 provides an example layout of a data center 200 housing severalelectrical equipment racks 202, 204, 206, 208, 210, 212, 214, 216, 218,220, 222, 224. Although the example layout includes twelve electricalequipment racks 202-224, a data center may alternately house more orfewer electrical equipment racks. Typically, a data center would housemany more electrical equipment racks.

In the example layout, four power feed circuits 226, 228, 230, 232 arederived from two RPPs 234, 236. The power feed circuits 226, 228, 230,232 deliver power to twelve electrical equipment racks 202-224. Two ofthe power feed circuits 226, 228 are single-phase circuits, and two ofthe power feed circuits 230, 232 are three-phase circuits. Connectionsof the power feed circuits 226-232 to infeeds 300, 302, 304, 306, 308,310, 312, 314, 316, 318, 320, 322, 324, 326, 328, 330, 332, 334, 336,338, 340, 342, 344, 346 of PDUs mounted in the electrical equipmentracks 202-224 are shown in FIG. 3.

Typically, each electrical equipment rack 202-224 (or cabinet) isprovided with two PDUs, each of which receives power from a differentpower source (e.g., RPP 234 or 236) and feed circuit 226-232. See, FIG.3. Thus, a first PDU may have an “A” infeed 300 that receives power froma first power feed circuit 230, and a second PDU may have a “B” infeed302 that receives power from a second power feed circuit 232, therebyproviding an electrical equipment rack 202 with power redundancy fromindependent/different power sources. Typically, to ensure theavailability of redundant power in the case of PDU failure, each PDUmounted within an electrical equipment rack is only loaded to about 40%of its power handling capacity.

FIG. 4 shows an example of a rack-mounted PDU 418. The PDU 418 includesIntelligent Power Modules (IPMs) 400, along with a communications module420 that provides communication functions, an environmental monitor 422,and an input power cord 424 with associated plug 426. The PDU 418according to this embodiment includes a housing that is verticallymountable in an equipment rack, although it will be understood thatother form factors may be used, including a horizontally mountablehousing. The IPMs 400 each include eight outlets 402-416 that supplypower to assets mounted in an electrical equipment rack. Such equipmentracks are well known, and often include several individual assets thatare used in operation of a data center. As is well known, numerousequipment racks may be included in a data center, and in variousembodiments each asset in each equipment rack may be monitored for powerusage through one or more associated IPMs 400. The visual display 428(shown displaying the numeral “57”) is disposed in the PDU 418, althoughin other embodiments the display might be external to the PDU 418 or notprovided.

In one embodiment, the power outlet module 400 includes eight outlets(402-416), each of NEMA 5-20R type, contained in a housing. It will beunderstood that this embodiment, and other embodiments described hereinas having NEMA 5-20R type outlets, are exemplary only. In otherembodiments, various other types of outlets can be alternately oradditionally provided. For example, the “outlets” can be other NEMAtypes (e.g., NEMA 5-15R, NEMA 6-20R, NEMA 6-30R or NEMA 6-50R) or any ofvarious IEC types (e.g., IEC C13 or IEC C19). It will also be understoodthat all “outlets” in a particular power outlet module 400, or othermodule-outlet described herein, need not be identical or orienteduniformly along the PDU 418. It also will be understood that the“outlets” are not limited to three-prong receptacles; alternatively, oneor more of the “outlets” can be configured for two or more than threeprongs in the mating male connector. It will also be understood that the“outlets” are not limited to having female prong receptacles. In any“outlet,” one or more of the “prong receptacles” can have a male orfemale configuration, as conditions or needs indicate. In general, andas used herein, female and male “prong receptacles” are termed“power-connection elements”. Furthermore, the principles describedherein are also applicable to devices that may be hard-wired into anoutlet module. While outlet module 400 of this embodiment includes eightoutlets, it will be understood that this is but one example and anoutlet module may alternately include a different number of outlets.

The housing for an outlet module may be any suitable housing for such adevice, as is known to one of skill in the art, and may be assembledwith other modules in a PDU. Such a housing generally includes a frontportion and a rear portion, the front portion of which is substantiallyplanar, and the rear portion of which is substantially planar andparallel to the front portion. The housing may also includelongitudinally extending side portions and transverse end portions. Thefront portion, rear portion, side portions, and end portions aregenerally orthogonal to each other in a generally rectangular orbox-type configuration. The housing can be made of any suitable,typically rigid, material, including, for example, a rigid polymeric(“plastic”) material. In at least certain embodiments, the front andrear portions are made from an electrically insulative material, whereasin other embodiments conducting materials are used for safe groundbonding. The side portions and the end portions may be integrallyformed, optionally along with the front portion or the rear portion.Furthermore, while the outlet module described in this embodimentincludes a housing, other embodiments may include an outlet module thatdoes not include a housing. For example, an outlet module may include anumber of outlets coupled together with no exterior housing, which maythen be installed into another piece of equipment.

Each outlet 402-416 is interconnected to the power source (directly orindirectly) through any of a number of well-known connection schemes,such as connection schemes using spade, lug, plug, screw, or othersuitable types of connectors. Furthermore, if desired, one or more ofthese electrical connectors can be located inside the housing or outsidethe housing, in embodiments where the power outlet module includes ahousing.

In some cases, a rack-mounted PDU having a network communicationinterface may be coupled to a network power manager over a network(e.g., over an Ethernet or the Internet), as shown in the block diagramof FIG. 5. A plurality of such PDUs may be coupled to the network powermanager, in the same or different ways. In this manner, characteristicsof the PDUs may be remotely configured, monitored or controlled over thenetwork using the network power manager. The network power manager maytake the form of a software tool residing on a desktop or notebookcomputer, server or mobile device (e.g., a phone, tablet or pad).

With reference to FIG. 5, an example block diagram of a PDU is shown anddescribed. The PDU 500 supplies power to one or more associatedcomputing assets. The PDU 500 is useable in a computer network 502, andmay communicate over the computer network 502 with a network powermanager 504. The network power manager 504 may reside on or bevirtualized on a server, workstation or other device that is used in themanagement of a data center or other enterprise management. The networkpower manager 504 issues network commands over a network communicationsconnection. The PDU 500 of this embodiment includes a power supply 506,a network interface card (NIC) 508 that has application firmware andhardware that interfaces to network the PDU 500 with other moduleswithin the PDU, and a power manager agent application 510. The PDU 500further includes a plurality of power outlets 512 arranged in a powerdistribution plugstrip, and an intelligent power module (IPM) 514. TheIPM 514, NIC 508, and power manager agent 510 are connected to thecomputer network 502. The intelligent power module 514 controls theapplication of power from the input power to a corresponding poweroutlet or outlets among the power outlets 512, and is in communicationwith the power manager agent application 510 to provide power and powercycling on-off for one or more of the corresponding power outlets. TheIPM 514 may also provide power state sensing and/or load-sensing withrespect to the corresponding power outlet(s) in response to one or morecommands. The IPM 514 in this embodiment includes a microprocessor 516used to control the power applied to a corresponding power outlet. Themicroprocessor 516 is also connected to a voltage sensing device 518 anda current sensing device 520 to sense the voltage and current atcorresponding individual power outlet(s). The microprocessor 516 usesthis information to determine the power supplied to an outlet, as willbe described in more detail below. The microprocessor 516 also receivesa power measurement from the input power supply 506 through an inputvoltage sensing device 522 and an input current sensing device 524.

The network power manager 504 of FIG. 5 communicates with the powermanager agent 510 and IPM 514. The network power manager 504 may receiveinformation from, and provide instructions to, the IPM 514 and powermanager agent 510. The network power manager 504 may also receiverelated power measurements from the IPM 514 and report power informationrelated to the PDU 500 and one or more individual outlets (and thuspower information for individual assets powered by the outlet) of thePDU 500.

As disclosed in FIG. 5, and as further disclosed in U.S. patentapplication Ser. No. 12/344,419, a network power manager may receivepower usage data for the power input(s) of a PDU and use the power usagedata to monitor the PDU and its power usage. This may include, forexample, monitoring the balance of power phases within the PDU.Monitoring the balance of power phases is useful, for example, inunderstanding how to reduce the power usage of the PDU and mitigate thelikelihood of overheating. Disclosed herein are systems, methods,software and devices that use the power usage data obtained for a numberof PDUs to monitor power usage external to the PDUs, such as the powerusage of power feed circuits that supply power to multiple PDUs.

In some cases, the PDU 500 may include other components or modules, suchas fuse modules, environmental monitors, and communications modules.

FIG. 6 provides an example of a method 600 for monitoring power usage.By way of example, the method can be performed by the network powermanager shown in FIG. 5. At block 602, the method 600 accesses powerusage data for power distribution unit infeeds of a plurality ofrack-mounted power distribution units. The power usage data maycomprise, for example, power readings or current readings taken at theinfeeds of the plurality of PDUs. In one embodiment, the power usagedata may include power usage data for the infeeds of the PDUs includedin the electrical equipment racks shown in FIGS. 2 & 3. At block 604,the method 600 accesses stored circuit descriptions that describeinterconnections of the power distribution unit infeeds to a number ofpower feed circuits. In one embodiment, the circuit descriptions maydescribe the interconnections of the PDU infeeds and power feed circuitsshown in FIG. 3.

At block 606, the method 600 transforms the plurality of rack-mountedpower distribution units into a power usage monitor for monitoring thepower usage of the power feed circuits. The transformation isaccomplished by aggregating at least some of the power usage data basedon the interconnections of the rack-mounted power distribution unitinfeeds to the number of power feed circuits. For example, in oneembodiment, power usage data is respectively aggregated for the infeedsof each respective power feed circuit shown in FIG. 3. Power usage datamay also be aggregated based on the interconnections of PDU infeeds toparticular lines of power. Aggregating power usage data by line of powercan be especially helpful in determining the distribution of power(e.g., balance or unbalance of power) between phases of a polyphasepower feed circuit. By way of example, power usage data may beaggregated by adding it.

At block 608, the method 600 outputs representations of the aggregatedpower usage data. Outputting the representations of aggregated powerusage data may take the form of displaying, storing or transmitting therepresentations. The representations of the aggregated power usage datamay take different forms, and in some cases may include power usagevalues (e.g., analog or digital representations of power usage values)or power usage status indicators (e.g., analog or digitalrepresentations indicating that power is being used, or that usagethresholds have been met or exceeded). As mentioned, the aggregatedpower usage data can convey the power usage for a line of power or powerfeed circuit. Alternately, power usage data can be aggregated for theinfeeds of a single PDU, a single cabinet, a row of cabinets, or anyother combination of infeeds or PDUs.

FIG. 7 provides an example of a power usage monitoring system 700comprising a circuit description receiving interface 702, a power usagecommunication interface 704, a memory subsystem 706 and a processingunit 708. By way of example, the power usage monitoring system 700 isshown to be part of a network power manager 710, such as the networkpower manager shown in FIG. 5.

The circuit description receiving interface 702 receives a number ofcircuit descriptions that describe interconnections of rack-mountedpower distribution unit infeeds to a number of power feed circuits. Thepower usage communication interface 704 receives power usage data forthe rack-mounted power distribution unit infeeds. The memory subsystem706 stores the received circuit descriptions and the power usage data.

The processing unit 708 is interconnected with the circuit descriptionreceiving interface 702 and the power usage communication interface 704and is programmed to receive the number of circuit descriptions and thepower usage data. In some cases, the interfaces 702, 704 may beprovided, at least in part, by configuring or programming the processingunit 708 to assume one or more different physical states. The processingunit 708 is also programmed to aggregate at least some of the powerusage data based on the interconnections of the rack-mounted powerdistribution unit infeeds to the number of power feed circuits. Theprocessing unit 708 is further programmed to output representations ofthe aggregated power usage data.

In some embodiments, part or all of the processing unit 708 andinterfaces 702, 704 may be provided as part of, or on, a commonintegrated circuit or printed circuit board. Part or all of the memorysubsystem 706 may also be provided on the integrated circuit or printedcircuit board. Alternately, the elements of the power usage monitoringsystem 700 may be provided as separate but interconnected components. Byway of example, the processing unit 708 may take the form of one or moremicroprocessors, digital signal processors, or microcontrollers. Also byway of example, the memory subsystem 706 may comprise both a memory anda memory controller. The memory may comprise, for example, one or moredevices for storing data, including random access memory (RAM), magneticRAM, read only memory (ROM), magnetic disk storage mediums, opticalstorage mediums, flash memory devices, main memory, core memory, cachememory, or other computer-readable mediums for storing information. Insome embodiments, the components of the power usage monitoring system700 may, individually or collectively, be implemented with one or moreApplication Specific Integrated Circuits (ASICs) adapted to perform someor all of the applicable functions in hardware. Alternatively, thefunctions may be performed by one or more other processing units (orcores), on one or more integrated circuits. In other embodiments, othertypes of integrated circuits may be used (e.g., Structured/PlatformASICs, Field Programmable Gate Arrays (FPGAs) and other Semi-CustomICs), which may be programmed in any manner known in the art. Thefunctions of each unit may also be implemented, in whole or in part,with instructions embodied in a memory, formatted to be executed by oneor more general or application-specific processing units.

In some embodiments, some or all of the elements of the power usagemonitoring system 700 may be provided as part of the network powermanager shown in FIG. 5, and may provide structures and functionalitythat facilitate power usage monitoring internal and external to a PDU(e.g., for branch circuits internal to the PDU, and for power feedcircuits external to the PDU). The elements of the power usagemonitoring system 700 may also provide structures and functionality forremotely configuring, monitoring or controlling the PDU via the networkpower manager. In some cases, the elements of the power usage monitoringsystem 700 may be provided as elements of a server computer.

The circuit description receiving interface 702 may in some casesreceive circuit descriptions that directly associate rack-mounted powerdistribution unit infeeds with power feed circuits. In other cases, thecircuit descriptions may indirectly associate rack-mounted powerdistribution unit infeeds with power feed circuits. For instance, thecircuit descriptions may associate PDU infeeds with particular lines ofthe power feed circuits, or the circuit descriptions may associate PDUswith power feed circuits. In these instances, the processing unit may beprogrammed to access or acquire correlations of power feed circuits andthe lines thereof, or correlations of PDUs and PDU infeeds.

The processing unit 708 may communicate with a number of PDUs over anetwork, via the power usage communication interface 704. In thismanner, the processing unit 708 may acquire/receive power usage datafrom the PDUs. The processing unit 708 may also, or alternately,communicate (via the power usage communication interface 704) with adata store in which some or all of the power usage data is stored.

In some embodiments, the power usage monitoring system 700 may furthercomprise a display on which the representations of the aggregated powerusage data are displayed. By way of example, the display may include acathode ray tube (CRT), liquid crystal display (LCD), desktop or laptopcomputer display, or mobile phone display. In some cases, the processingunit 708 can be programmed to output the representations of theaggregated power usage data as data points for generating a trend charton the display, or as data points for generating a phase distributionchart on the display. Particular examples of such a trend chart andphase distribution chart will be provided later in this description.

Representations of the aggregated power usage data may be conveyed to auser locally or remotely. For example, the representations may bedisplayed on a display that is local to a server that provides a networkpower manager; or the representations may be transmitted over a networkfor display by a remote computer or mobile phone.

The representations of the aggregated power usage data may include, forexample, power usage values or power usage status indicators. Powerusage values may include, for example, power or current values, with orwithout units. Power usage status indicators may include, for example,single or multi-bit status descriptors, or instructions to set or resetlight emitting diode (LED) status indicators, audible alarms, or statusindicators included within a display.

FIGS. 8-15 illustrate screen images 800, 900, 1000, 1100, 1200, 1300,1400, 1500 of a graphical user interface (GUI) 820. The GUI 820 may beprovided by, or in conjunction with, a power usage monitoring system.Some of the screen images may be considered part of the circuitdescription receiving interface of a power usage monitoring system (ormay be considered to expose the circuit description receiving interfaceto a user). These screen images (e.g, the screen images shown in FIGS.8-13) may provide graphical tools that enable a user to associate PDUinfeeds with power feed circuits and/or lines of the power feedcircuits. The screen images shown in FIGS. 14 & 15 may be consideredpart of an output interface of a power usage monitoring system.

FIG. 8 illustrates a screen image 800 from which a New Circuit icon 802may be graphically selected (or pressed) to start the process ofentering a new circuit description via the GUI 820. FIG. 9 illustrates aNew Circuit screen 900 that pops up following a press of the New Circuitbutton 802. The New Circuit screen 900 includes a text field 902 forreceiving a name of a new power feed circuit. The New Circuit screen 900also includes a drop-down selection tool 904 for selecting a CircuitType. As shown in the screen image 1000 of FIG. 10, the Circuit Typeselections may include a Single Phase circuit type and a 3 Phase circuittype. Upon selecting a 3 Phase circuit type, a drop-down selection tool1102 may be provided for selecting three-phase (Enclosure), two-phase(XY, YZ or ZX) or single-phase (Line 1, Line 2, Line 3) connections ofPDU infeeds to the 3 Phase circuit. See, FIG. 11. Line name text fields1104, 1106, 1108 may be provided for receiving custom names for thevarious lines included in a three-phase circuit. If Enclosures (e.g.,racks or CDUs) are specified, the manner in which they are connected toa 3 Phase circuit may be retrieved from information that is maintainedby, retrieved by, or input into a network power manager. Upon selectinga Single Phase circuit type (see FIG. 12), a user may be provided with adrop-down selection tool 1202 for selecting which line of primary inputpower the Single Phase circuit is derived from, as well as a Line Nametext field 1204 for receiving a name of the single-phase line includedin the Single Phase circuit.

Once a Circuit Type and Line have been selected, a user may select oneor more infeeds from a list 1302 of provided or discovered infeeds. See,e.g., the screen image 1300 shown in FIG. 13. A selected infeed 1304 maybe dragged and dropped into an Included window 1306, thereby indicatingthat a connection exists between the infeed and the selected circuit andline. Upon saving the set of included infeeds, the lines and devicesconnected to the infeeds listed in the Included window 1306 arepopulated in the Circuit Contents window 1308. By way of example,infeeds are identified in the list of infeeds 1302 by their infeed Nameand corresponding CDU Name. In the example screen, a CDU Name takes theform of an internet protocol (IP) address of the CDU. An infeed Name maybe changed by first selecting it using, for example, two mouse clickshaving a particular time relation. FIG. 13 shows a specification ofinterconnections between a number of PDU infeeds (e.g., TowerA_InfeedA)and a particular line of power (e.g., Line 1) in a particular power feedcircuit (e.g., Demo Circuit).

Having described how the screens shown in FIGS. 8-13 may be used toenter a number of circuit descriptions into a GUI 820 of a power usagemonitoring system, a couple of screens 1400, 1500 for monitoring powerusage will now be described. FIG. 14 illustrates a first of thesescreens. The screen 1400 provides a Summary tab/frame 1402 for thedon_A_test circuit. The frame 1402 includes sub-frames labeled CircuitInformation 1404, Circuit Recent Events 1406, Line Distribution 1408,Trend 1410 and Circuit Contents 1412. The Circuit Information sub-frame1404 provides, for example, the Name of the circuit, the percentagewhich it is Out of Balance (in the case of a three-phase circuit type),and Circuit Status, Current Status and Power Status indicators. TheCircuit Recent Events sub-frame 1406 lists recent circuit events ofinterest, such as Alarms that have triggered. The Line Distributionsub-frame 1408 provides a phase distribution chart for both current andpower. This information is especially useful for load balancing powerbetween the different phases. The Trend sub-frame 1410 provides a trendchart, and by way of example shows Circuit Total Power over time. Thetrend chart is useful in analyzing the effects of PDUs and/or theirpowered equipment being powered up, powered down, or used to varyingdegrees (e.g., at peak and non-peak usage times). This information isespecially useful for capacity planning. The Circuit Contents sub-frame1412 provides a summary of total power and total current per line ofpower in a circuit and provides an expandable menu for expanding orcollapsing the contents (e.g., infeeds) of each line of power. The Trendand Line Distribution tabs 1414, 1416 may be respectively selected tosee enlarged or alternate trend and line distribution charts orinformation.

The screen 1500 shown in FIG. 15 provides a Summary tab/frame 1502 for asingle line of power named “Line 3”. The frame 1502 includes sub-frameslabeled Line Information 1504, Line Recent Events 1506, Trend 1508 andLine Contents 1510. The Line Information sub-frame 1504 provides, forexample, the Name of the line, the name of the Circuit the line belongsto, Line Status, and Current Status and Power Status indicators. TheLine Recent Events sub-frame 1506 lists recent line events of interest,such as Alarms that have triggered. The Trend sub-frame 1508 provides atrend chart, and by way of example shows Line Total Power over time. Thetrend chart is useful in analyzing the effects of PDUs and/or theirpowered equipment being powered up, powered down, or used to varyingdegrees (e.g., at peak and non-peak usage times). The Line Contentssub-frame 1510 provides a summary of total power and total current usedper infeed connected to the selected line of power. The Trend tab 1512may be selected to see an enlarged or alternate trend charts orinformation.

In some cases, the GUI 820 shown in FIGS. 8-15 may be generated by theprocessing unit 708 shown in FIG. 7. For purposes of this description, aGUI is considered to be generated by a processing unit regardless ofwhether the processing unit plays a higher level or lower level role ingenerating the GUI. For example, a processing unit may generate a GUIdisplayable on a display by assembling and outputting substantial partsor all of the GUI's screen images. In other embodiments, for example, aprocessing unit may simply provide instructions that cause memory, videoor other sub-systems to assemble or output appropriate screen images atappropriate times.

In some cases, software, firmware, middleware, microcode, a hardwaredescription language for instantiating a power usage monitor may beprovided on a computer readable medium 1600. See, FIG. 16. Inparticular, the computer readable medium 1600 may store instructions1602, 1604, 1606, 1608 that, when executed by a computer, cause thecomputer to: 1) access power usage data of rack-mounted powerdistribution unit infeeds 1602 (e.g., over a network or in a database);2) access stored circuit descriptions describing interconnections of therack-mounted power distribution unit infeeds to a number of power feedcircuits 1604 (e.g., in a database); 3) aggregate at least some of thepower usage data based on the interconnections of the rack-mounted powerdistribution unit infeeds to the number of power feed circuits 1606; and4) output representations of the aggregated power usage data 1608. Forpurposes of this description, a “computer” is any system of device thatis capable of executing instructions, such as, but not limited to: aserver, a workstation, a personal computer, a mobile phone, a tabletcomputer, or a master PDU that receives power usage data from otherPDUs. A “computer readable medium” is any medium capable of storinginstructions that are executable by a computer, including, but notlimited to: a portable or fixed storage device, an optical storagedevice, a wireless channel, a SIM card, other smart cards, and variousother mediums capable of storing, containing or carrying instructions ordata. Some of these computer readable mediums are non-transitory.

In some cases, a method 1700 of facilitating power usage monitoring ofpower feed circuits may comprise providing a computer 1702 programmedto: 1) access power usage data of rack-mounted power distribution unitinfeeds 1704; 2) access circuit descriptions describing aninterconnection of rack-mounted power distribution unit infeeds to anumber of power feed circuits 1706; 3) aggregate at least some of thepower usage data based on the interconnections of the rack-mounted powerdistribution unit infeeds to the number of power feed circuits 1708; and4) output representations of the aggregated power usage data 1710. See,FIG. 17.

The systems, devices, methods, and software described herein are usefulnot only for monitoring the power usage of power feed circuits thatsupply power to equipment racks in a data center, but are useful inmapping and managing the physical infrastructure of the power systemsfeeding one or many electrical equipment racks, thereby enabling a userto determine where losses in efficiency exist as a result of conditionssuch as power system overload, underuse or imbalance. These conditionscan exist, and can be monitored, at the PDU level, at the cabinet level,within a row of cabinets, within a zone, or at any other group, level orlocation that a user defines.

Although the examples provided herein focus on power usage monitoringfor the power feed circuits that supply power to rack-mounted PDUs, theteachings herein also apply to power usage monitoring for other types ofpower feed circuits, such as the power feed circuits that supply powerto floor-mounted and other types of PDUs. That said, peculiar advantagescan be realized by aggregating the power usage data of rack-mountedpower distribution unit infeeds. For example, rack-mounted PDUs aretypically the most downstream PDU of a power distribution system, andthus, the power flowing through these PDUs is impacted by the powerflowing through the entire power supply chain. Furthermore, for example,rack-mounted PDUs tend to be the most numerous type of PDU in a datacenter or similar facility. Collecting data at the numerous infeeds ofthese PDUs therefore provides the most data points for assessing thedistribution and balance of power in a data center.

It should be noted that the methods, systems, devices and computerreadable mediums discussed above are intended merely to be examples. Itmust be stressed that various embodiments may omit, substitute, or addvarious procedures or components as appropriate. For instance, it shouldbe appreciated that, in alternative embodiments, the methods may beperformed in orders different from that described, and that variousprocedures may be added, omitted or combined. Also, features describedwith respect to certain embodiments may be combined in various otherembodiments. Different aspects and elements of the embodiments may becombined in a similar manner. Also, it should be emphasized thattechnology evolves and, thus, many of the elements are exemplary innature and should not be interpreted to limit the scope of theinvention.

Specific details are given in the description to provide a thoroughunderstanding of the embodiments. However, it will be understood by aperson of ordinary skill in the art that the embodiments may bepracticed without these specific details. For example, well-knowncircuits, processes, algorithms, structures, and techniques have beenshown without unnecessary detail in order to avoid obscuring theembodiments.

Also, it is noted that certain embodiments are described using flowdiagrams or block diagrams. Although each may describe procedures oroperations that occur sequentially, many of the procedures or operationscan be performed in parallel or concurrently. In addition, the order ofthe procedures or operations may be rearranged. A process may also haveadditional steps not included in the figure.

Furthermore, embodiments may be implemented by hardware, software,firmware, middleware, microcode, hardware description languages, or anycombination thereof. When implemented in software, firmware, middlewareor microcode, the program code or code segments to perform the necessarytasks may be stored in a computer readable medium. A processing unit mayperform the necessary tasks.

Having described several embodiments, it will be recognized by those ofskill in the art that various modifications, alternative constructions,and equivalents may be used without departing from the spirit of theinvention. For example, the above elements may merely be components of alarger system, wherein other rules may take precedence over or otherwisemodify the application of the invention. Also, a number of steps may beundertaken before, during, or after the above elements are considered.Accordingly, the above description should not be taken as limiting thescope of the invention.

We claim:
 1. A power usage monitoring system, comprising: a circuit description receiving interface, the circuit description receiving interface receiving a number of circuit descriptions describing interconnections of power distribution unit infeeds to a number of power feed circuits; a power usage communication interface, the power usage communication interface receiving power usage data for the power distribution unit infeeds; a memory subsystem, the memory subsystem storing the received circuit descriptions and the power usage data; and a processing unit interconnected with the circuit description receiving interface and the power usage communication interface, the processing unit programmed to receive the number of circuit descriptions and the power usage data, aggregate at least some of the power usage data based on the interconnections of the power distribution unit infeeds to the number of power feed circuits, and output representations of the aggregated power usage data.
 2. The power usage monitoring system of claim 1, wherein the circuit description receiving interface receives circuit descriptions that associate power distribution unit infeeds with lines of the power feed circuits.
 3. The power usage monitoring system of claim 1, wherein the circuit description receiving interface receives circuit descriptions that associate power distribution units with power feed circuits.
 4. The power usage monitoring system of claim 1, wherein the processing unit communicates with a number of power distribution units, over a network, via the power usage communication interface.
 5. The power usage monitoring system of claim 1, wherein the processing unit communicates via the power usage communication interface with a data store in which some or all of the power usage data is stored.
 6. The power usage monitoring system of claim 1, further comprising a display on which the representations of the aggregated power usage data are displayed.
 7. The power usage monitoring system of claim 1, wherein the processing unit is programmed to output the representations of the aggregated power usage data as data points for generating a trend chart on a display.
 8. The power usage monitoring system of claim 1, wherein the processing unit is programmed to output the representations of the aggregated power usage data as data points for generating a phase distribution chart on a display.
 9. The power usage monitoring system of claim 1, further comprising a network interface over which the representations of the aggregated output power usage data are transmitted.
 10. The power usage monitoring system of claim 1, wherein the representations of the aggregated power usage data include power usage values.
 11. The power usage monitoring system of claim 1, wherein the representations of the aggregated power usage data include power usage status indicators.
 12. The power usage monitoring system of claim 1, wherein the power usage data includes power readings.
 13. The power usage monitoring system of claim 1, wherein the power usage data includes current readings.
 14. The power usage monitoring system of claim 1, wherein the processing unit is further programmed to aggregate at least some of the power usage data based on the interconnections of power distribution unit infeeds to lines of the number of power feed circuits.
 15. The power usage monitoring system of claim 1, wherein the processing unit is further programmed to generate a graphical user interface, the graphical user interface exposing the circuit description receiving interface to a user of a display and providing graphical tools for associating the power distribution unit infeeds with the power feed circuits.
 16. The power usage monitoring system of claim 1, wherein the processing unit is further programmed to generate a graphical user interface, the graphical user interface exposing the circuit description receiving interface to a user of a display and providing graphical tools for associating the power distribution unit infeeds with lines of the power feed circuits.
 17. A non-transitory computer readable medium storing instructions that, when executed by a computer, cause the computer to: access power usage data for power distribution unit infeeds; access stored circuit descriptions describing interconnections of the power distribution unit infeeds to a number of power feed circuits; aggregate at least some of the power usage data based on the interconnections of the power distribution unit infeeds to the number of power feed circuits; and output representations of the aggregated power usage data.
 18. A method of monitoring power usage, comprising: accessing power usage data for power distribution unit infeeds of a plurality of power distribution units; accessing stored circuit descriptions describing interconnections of the power distribution unit infeeds to a number of power feed circuits; transforming the plurality of power distribution units into a power usage monitor for monitoring power usage of the power feed circuits by aggregating at least some of the power usage data based on the interconnections of the power distribution unit infeeds to the number of power feed circuits; and outputting representations of the aggregated power usage data. 